King Richard I of England invaded the island of Cyprus in the year 1191 as part of the Third Crusade. He ordered a castle built there, but it only lasted thirty years before an earthquake destroyed it, and it was never rebuilt. The site of the ruins turned out to be an amazing opportunity for archeological research -in its toilet!

As castles go, Saranda Kolones had a pretty poor run. But two University of Cambridge researchers recently realized that, precisely thanks to the castle’s short use, a priceless treasure had been left behind in the Saranda Kolones’ bowels. One of the centuries-old castle latrines (read: ancient toilet), they found, was still full of dried-up poo. That feces, they thought, could provide valuable insight into what kind of parasites plagued the former residents’ guts. And because only 30 years’ worth of waste clogged the ancient sewage system, those parasites could provide specific insight into what ailed medieval crusaders. The researchers rolled up their sleeves and collected samples from the dessicated cesspool.

They found plenty of parasites, almost 900 years later. They identify them for us, and describe how they would have affected the Crusaders, in an article at Surprising Science. Link